What is it about?

Bilabial trills are speech sounds made with vibrations of the lips. Most babies produce them spontaneously, but very few languages around the world use bilabial trills systematically, mostly because they are difficult to integrate into connected speech. Nevertheless, bilabial trills have not just emerged, but also persist in a group of 23 languages spoken on the island of Malekula in the Republic of Vanuatu in the South Pacific. This paper finds that the emergence and persistence of bilabial trills in Malekula languages has been supported by a number of factors, including the structure and history of these particular languages, but also social factors like attaching in-group identity to these unusual speech sounds, which are both auditorily and visually prominent.

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Why is it important?

Our study demonstrates that unusual sound change can be explained by adopting a multi-faceted approach. This includes looking at factors related to the languages themselves, but also at social and historical factors, such as language contact and identity marking through linguistic features. In general, looking at the interplay of different factors can draw a better picture of the processes involved in language evolution.


This article grew from my research on the Ahamb language. Ahamb is a Malekula language that has not just one, but two contrastive bilabial trills - one is pronounced with a slight m-like sound preceding it, while the other one is not, like in the words ᵐbbus 'squeeze' and ppus 'flower' (<ᵐbb> and <pp> stand for the two bilabial trills). When I was first introduced to an Ahamb speaker in 2014, I became very curious about these sounds and spent many months living with the Ahamb people in order to describe the sound system and structure (grammar) of their language. The data for the other Malekula languages come from the work of other linguists on Malekula, but also from the Vanuatu Voices database (https://vanuatuvoices.clld.org/languages), which has allowed us to look at all Malekula languages consistently. This article thus demonstrates the importance of both in-depth research on particular languages and the creation of larger databases.

Tihomir Rangelov
Max Planck Institute for Evolutionary Anthropology

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This page is a summary of: A multifaceted approach to understanding unexpected sound change, Diachronica, February 2023, John Benjamins,
DOI: 10.1075/dia.21051.ran.
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